Three years ago I soldered my first custom-designed PCBs, a set of ESP8266-powered temperature sensors for my apartment!

The original design worked with the ESP8266 modules I had at the time but hasn’t with recent modules (I think I forgot to pull the chip-enable wire high?).

Wemos D1 Mini Carrier Board

This is a spinoff project of my dedicated, single-purpose temperature sensor boards. Instead of trying to be as cheap and small as possible it is intended to be an easy way to connect I2C sensors to the Wemos D1 Mini and probably to esphome.

Further documentation on github.com/djbeadle/ESP8266-Temperature-Sensor.

Board

Top

Bottom

Notes

• Designed in KiCad at NYC Resistor where I first was shown the joy of Esphome (compared to writing your own firmware by!).

• First PCB order December, 2021.

Pinout Details

• 4x I2C, two of each arrangment: SDA-SCL-GND-3.3V and SCL-SDA-3.3V-GND (SDA pin D2, SCL pin D1)
• 2x 1-Wire pinouts arranged as D0-3.3V-GND and 3.3V-D0-GND
• 1x push-button footprint (3.3V and pin D8)
• 1x photoresistor & resistor footprint (3.3V, A0, and GND via a resistor footprint, 10k generally works well)
• 1x footprint for a terminal block connector (Check your specific Wemos D1 Mini information to see what input voltage it is capable of handling on the 5V pin!)